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Obtaining Estimates
Within interval conditional probabilities
–Use A, B, C  to estimate Pr(T > 1)
–Use A, B       to estimate Pr(T > 2 | T > 1)
–Use A           to estimate Pr(T > 3 | T > 2)
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Multiply to obtain unconditional cumulative survival
–Pr(T > 1)
–Pr(T > 2) =   Pr(T > 2 | T > 1)  Pr(T > 1)
–Pr(T > 3) =   Pr(T > 3 | T > 2)  Pr(T > 2)